Etiology of mental traits and diseases Flashcards
Diseases through NvsN
Diseases used to be explained through the nurture concept:
Autism = refrigerator mother
Homosexuality = Overly present mother
Etiology
Causation of a disease or condition.
Most brain conditions are multifactorial
Both genetic and environmental factors are involved in etiology
Heritability
Proportion of variance in symptoms that is explained by the variance in genetic factors
E.G
Depression = 40-50%
ADHD = 75%
Autism, bipolar, shcizophrenia = 80%
The classic theory
Single abnormal gene - abnormal gene product - neuronal malfunction - mental illness.
However one single abnormal gene is not sufficient enough to cause mental disorders
Endophenotype approach
It’s hard to map the pathway from genotype to phenotype so we use endophenotypes instead.
They are measurable, inheritable and closely linked to diseases.
More precisely measurable than illness.
Two types;
Biological
Symptom/system
Biological endophenotypes
Measurable biological phenomena
- Electrophysiological response to startle
- Neuroimaging response to information processing
- Activation of certain brain circuit
Symptom/system Endophenotypes
Single symptoms associated with mental illness
-Insomnia
-Executive dysfunction
-Hallucinations
-Poor fear conditioning
-Anhedonia - lack of pleasure
Risk genes
They are not necessary sufficient to cause mental illness.
They need to be in combination with environmental risk factors (stress, life events, physical illness etc)
Social-ecological framework
No single factor can explain;
Factors;
Individual
Relationship
Environmental factors
Pre-peri natal factors
Maternal stress during pregnancy
Maternal nutritional deficiency
Maternal use of tobacco/alcohol/drugs/medication
Birth complications
Perinatal nutritional deficiency
Maternal separation
Environmental factors
Abuse; sexual, physical or emotional
-Neglect
-Poor parental care
-Infections
-Toxins
-Brain trauma
-Drug use
-Stressful life events
